/Engine/Source/Runtime/Slate/Public/Framework/Application/SlateApplication.h
Get the index of a registered pre-processor.
The index of the pre-processor, or INDEX_NONE if not registered.
int32 FindInputPreProcessor ( [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< class [IInputProcessor](API\Runtime\Slate\Framework\Application\IInputProcessor) > InputProcessor ) const